Heat Stress in Farmed Chickens: A Growing Welfare Crisis

As global temperatures rise, heat stress in commercial poultry is becoming one of the most significant welfare challenges in the industry. Broilers and laying hens are highly vulnerable, and the consequences range from suffering to mass mortality events.

Key Facts

Chickens cannot sweat; they rely on panting and wing-spreading to dissipate heat, which becomes ineffective above 35°C.
Modern fast-growing broiler breeds have high metabolic rates that generate excess body heat, making them especially vulnerable to heat stress.
During heat waves, poultry farm mortality events killing tens of thousands of birds in a single facility have been documented worldwide.
Chronic heat stress suppresses immune function, reduces feed intake, and causes intestinal barrier dysfunction in broilers.
Electrolyte imbalances from prolonged panting disrupt blood pH, causing respiratory alkalosis and organ damage.
Evaporative cooling systems, tunnel ventilation, and reduced stocking density are the most effective heat mitigation strategies.

Welfare Considerations

Heat stress causes acute suffering in chickens — panting, prostration, and convulsions precede death in severe cases. Chronic exposure to elevated temperatures causes a more insidious welfare impact through immune suppression, reduced gut health, and increased disease susceptibility. As climate change increases the frequency of extreme heat events, farms without adequate cooling infrastructure face escalating welfare and production crises. Slower-growing breeds, which generate less metabolic heat, are significantly more resilient. Welfare-forward heat management combines building design, stocking density limits, breed selection, and monitoring systems that trigger cooling responses before heat stress becomes acute.

What You Can Do

Choose slower-growing breed chicken products (labelled as such by welfare schemes) that are more heat-resilient.
Support stronger heat stress mitigation requirements in poultry welfare regulations.
Reduce chicken consumption, particularly in summer when heat stress events are most likely.
Advocate for mandatory cooling system requirements in commercial poultry licensing.
Learn about climate-poultry welfare connections and share information during heat wave coverage.